At 15, Alistair Crane was weeding the drive at his father’s offices to earn money while other kids his age were “drinking White Ace on park benches”, as he puts it.

At 16, he left school for a job selling classified ads at the Daily Express. By 21, he’d been appointed head of media solutions at the Nokia-owned satnav company Navteq. And at 23, frustrated with senior management, he left the company to set up his own firm, Grapple Mobile, which develops mobile apps for brands.

It’s an explosive career trajectory for a man with only GCSE qualifications and little technical knowledge. Now 26 and chief executive of Grapple, Crane plays down the risk he took in setting up the company.

“I had a stack of clients at Nokia all asking me to help build mobile apps and websites, and not just for Nokia. My superiors didn’t want to know. If it’s not Nokia, they’re not interested. So I did what any sensible 23-year-old would do: I found someone with a lot more experience and significant financial backing and teamed up with him.”

That someone was serial entrepreneur Jamie True, who co-founded the venture with Crane and attracted six other seed investors. However, they encountered their first hurdle when it came to banks. “We were totally unproven,” Crane says. “So my bank made me provide three times the liquidity [for a loan]. That was a blessing and a curse. I had to go back to my investors, but they really put me on rocket fuel — significant investment, multi-millions.”

Initially, Grapple’s unique selling point was a development platform it acquired from a Canadian company that allowed it to write code that would work on more than 550 devices, rather than coding for each handset. Grapple’s first big break was Costa Coffee and Premier Inn owner Whitbread which, Crane, says “gave us the opportunity to prove ourselves”.

Last year, they developed a Premier Inn Booking app for Whitbread, which now makes £2.5 million a month and accounts for 47% of same-day bookings. Its success did not go unnoticed. After just seven months in business, Crane and True received an offer of £15 million for the firm.

“It was easy for me to say ‘yeah, I’d love to sell’ at 24 or 25 and become a very rich man, but there were people around who had sold companies for a lot more than we were being offered and they said it would be such a shame for us to sell now,” Crane says.

The pair rebuffed the offer, and Grapple continued to grow, working with companies such as McDonald’s, Hertz, Adidas, Lloyds Bank, Procter & Gamble and Pfizer. Its latest success is the Halifax Home Finder app, which allows smartphone users to point their device’s camera at their surrounding area and instantly view house-price data and Halifax loan rates about properties on the market nearby.

Crane is a natural salesman. He has a breezy charm and practised off-handedness that makes it easy to see why he has been able to sell to the world’s biggest companies. As Grapple’s apps become more complex, the company increasingly codes for each mobile rather than use its platform. What attract customers these days are Grapple’s track record and Crane’s pitch. “From the age of 16, I’ve been selling to brands,” he says. “I was selling classified ad space to SMEs, then moved to the display world and then the digital world.”

It would make sense for Crane to sell Grapple, and he admits: “It wouldn’t surprise me if in the next couple of years we did.”

The company that made an offer in 2010 came back to the table this year and Crane says there are five potential acquirers with which they keep in regular contact. But for now Crane is focusing on growing Grapple. The firm has just gone into acquisition mode and is looking to expand in the US, where it has an office in New York.

“Next year, you’ll find there are some quite interesting opportunities for businesses like us to acquire or merge with like-minded business not just in the UK but abroad as well,” Crane says, adding confidently: “If we only double our revenue, I’d think that was modest.”

GRAPPLE MOBILE

Founded: 2006

Staff: 85

Turnover: £5 million this year; £10 million projected next year

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